With development of the mobile Internet and smartphones, image compression has made a new progress. A major drive of researches of the industry for static image compression efficiency is application of mobile media sharing. Because smartphones have become an integration of media collection and application, a camera of a smartphone may capture an image with resolution of over 8 megapixels. Images have become a major media form in a rich media format of the mobile Internet, and a webpage browsed by using a mobile phone includes a large quantity of images; the popularity of socialized media applications such as Weibo and WeChat also makes rapid image sharing become necessary.
Generally, the Joint Photographic Experts Group (JPEG) compression standard has 10 times compression efficiency in a case in which subjective quality stays equivalent before and after compression, and this compression efficiency cannot meet requirements of compression, uploading, and sharing of an existing high-resolution image. Currently, in some applications, for example, Sina Weibo, downsampling is first performed on resolution of an image, and then a method of the JPEG compression standard is used to perform coding and compression, which may reduce resolution of a high-resolution image by approximately 1/16, but greatly affects subjective quality of the image.